This invention relates to farm vehicles adapted for backward operation such as back plowing. To facilitate backward operation, such a vehicle comprises steering handles reversible relative to the vehicle body by oscillating on a cylindrical column securedly standing on a transmission case, and a switch mechanism for clutch connection adapted to automatically select a combination for integral rotation from a pair of drive rotatable elements interlocked with a pair of right and left control means mounted on the steering handles and a pair of driven rotatable elements interlocked with a pair of right and left steering clutches mounted in the transmission case by sliding a pair of interlocking elements integrally slidable with a slidable and lockable control rod, whereby the steering clutches are operated smoothly and correctly whether the steering handles are in a position for forward traveling or a position for backing.
Conventional farm vehicles of this type are equipped with an automatic switch mechanism for steering clutch connection comprising a cam and a cam follower to press and slide the control rod toward one end thereof with an oscillation of the steering handles from the position for forward traveling to the position for backing or vice versa, and a spring to cause a return slide of the control rod toward the other end thereof, to thereby automatically switch the clutch connection by means of the oscillations of the steering handles. In the above arrangement, the automatic sliding performance of the control rod toward one end by the camming action may be maintained excellently and reliably over a long period of time, but the automatic sliding performance of the control rod toward the other end tends to grow poor in a short time due to deterioration in the elasticity of the spring used. Consequently, a smooth automatic switching of the clutch connection cannot last long, and trouble with clutching operation can arise easily.